Vibration actuator

Abstract

A vibration actuator includes a substantially rod-shape vibration member, and an electro-mechanical energy conversion element for vibrating the vibration member. The vibration member is vibrated by mechanical energy from the conversion element, thereby moving a member contacting the vibration member, and the vibration member relative to each other. A first notch which is notched in the radial direction and a second notch which is notched in the axial direction to be contiguous with the first notch are formed in the vibration member.

What is claimed is: 
     
       1. A vibration actuator comprising: a substantially rod-shape vibration member, said vibration member including a recess formed therein, the recess including a first recess portion formed about the entire circumference of the vibration member and extending radially inward from the outer circumference of the vibration member, and a second recess portion extending in an axial direction of the vibration member, the second recess portion being located at a radially interior portion of the first recess portion;   an electro-mechanical energy conversion element portion for generating a vibration in said vibration member; and   a contact member contactable to said vibration member and arranged for receiving the vibration therefrom to cause relative movement between said vibration member and said contact member.   
     
     
       2. A vibration actuator according to claim 1, wherein said first and second recess portions are annular. 
     
     
       3. A vibration actuator according to claim 2, wherein said second recess portion has a truncated conical cross-section. 
     
     
       4. A vibration member according to claim 1, wherein the vibration generated in said vibration member by said electro-mechanical energy conversion element portion causes a contact portion of said vibration member to move in a circular or elliptic motion. 
     
     
       5. A vibration member according to claim 4, wherein said electro-mechanical conversion element portion comprises a plurality of electro-mechanical energy conversion elements which are stacked in the axial direction of said vibration member. 
     
     
       6. A vibration member according to claim 5, wherein said plurality of electro-mechanical energy conversion elements include a plurality of first piezoelectric elements each having an electrode configuration arranged to be in special phase with each other, a plurality of second piezoelectric elements each having an electrode configuration and arranged to have a spacial phase difference from said first piezoelectric elements, and a third piezoelectric element forming a sensor. 
     
     
       7. An apparatus for moving an object to be moved using a vibration actuator as a driving source, the apparatus comprising: a vibration actuator comprising: a substantially rod-shape vibration member, said vibration member including a recess formed therein, the recess including a first recess portion formed about the entire circumference of the vibration member and extending radially inward from the outer circumference of the vibration member, and a second recess portion extending in an axial direction of the vibration member, the second recess portion being located at a radially interior portion of the first recess portion;   an electro-mechanical energy conversion element portion for generating a vibration in said vibration member; and   a contact member contactable to said vibration member and arranged for receiving the vibration therefrom to cause relative movement between said vibration member and said contact member; and     a movable object functionally engagable to one of said vibration member and said contact member.   
     
     
       8. An apparatus according to claim 7, wherein said apparatus is a printing apparatus, and said contact member is a movable member for feeding a sheet in the printing apparatus. 
     
     
       9. An apparatus according to claim 7, wherein said apparatus is a printing apparatus, and said contact member is a movable member for moving a carriage in the printing apparatus. 
     
     
       10. A vibration actuator comprising: a substantially rod-shape vibration member comprising a central shaft portion, a first elastic member portion supported on said central shaft portion at a first axial location, and a second elastic member portion located adjacent said first elastic member and supported on said central shaft portion at a second axial location, at least one of said first and second elastic member portions having an axial length and being supported on said central shaft portion along only a portion of the axial length of said at least one elastic member portion;   an electro-mechanical energy conversion element for generating a vibration in said vibration member; and   a contact member contactable to said vibration member and arranged for receiving the vibration therefrom to cause relative movement between said vibration member and said contact member.   
     
     
       11. A vibration actuator according to claim 10, wherein said at least one elastic member portion is threadably coupled to said central shaft portion. 
     
     
       12. A vibration actuator according to claim 10, wherein each of said first and second elastic member portions has an axial length and is supported on said central shaft portion along only a portion of the axial length of said elastic member portion. 
     
     
       13. A vibration actuator according to claim 10, wherein said at least one elastic member portion is supported on said central shaft portion at only a portion of the axial length thereof by forming a recess in said at least one elastic member portion extending in a direction of the axial length thereof between said at least one elastic member portion and said central shaft portion, one end of said recess terminating at a supporting portion of said at least one elastic member portion, and the other end of said recess being open. 
     
     
       14. A vibration actuator according to claim 10, wherein said second elastic member portion consists of a material having a specific gravity different from a specific gravity of said first elastic member portion. 
     
     
       15. An apparatus for moving an object to be driven using a vibration actuator as a driving source, the apparatus comprising: a vibration actuator comprising: a substantially rod-shape vibration member comprising a central shaft portion, a first elastic member portion supported on said central shaft portion at a first axial location, and a second elastic member portion located adjacent said first elastic member and supported on said central shaft portion at a second axial location, at least one of said first and second elastic member portions having an axial length and being supported on said central shaft portion along only a portion of the axial length of said at least one elastic member portion;   an electro-mechanical energy conversion element for generating a vibration in said vibration member; and   a contact member contactable to said vibration member and arranged for receiving the vibration therefrom to cause relative movement between said vibration member and said contact member; and     a movable object functionally engagable to one of said vibration member and said contact member.   
     
     
       16. An apparatus according to claim 15, wherein said apparatus is a printing apparatus, and said contact member is a movable member for feeding a sheet in the printing apparatus. 
     
     
       17. An apparatus according to claim 15, wherein said apparatus is a printing apparatus, and said contact member is a movable member for moving a carriage in the printing apparatus. 
     
     
       18. A vibration actuator according to claim 13, wherein said recess is annular and has a truncated conical cross-section. 
     
     
       19. A vibration actuator comprising: a substantially rod-shape vibration member, said vibration member including a first recess formed about the entire circumference of the vibration member and extending radially inward from the outer circumference of the vibration member, and a second recess contiguous with said first recess and extending in an axial direction of the vibration member, the second recess being located at a position radially interior to the first recess;   an electro-mechanical energy conversion element portion for generating a vibration in said vibration member; and   a contact member contactable to said vibration member and arranged for receiving the vibration therefrom to cause relative movement between said vibration member and said contact member.   
     
     
       20. A vibration actuator according to claim 19, wherein said first and second recesses are annular. 
     
     
       21. A vibration actuator according to claim 20, wherein said second recess has a truncated conical cross-section. 
     
     
       22. A vibration actuator according to claim 19, wherein the vibration generated in said vibration member by said electro-mechanical energy conversion element portion causes a contact portion of said vibration member to move in a circular or elliptic motion. 
     
     
       23. An apparatus for moving an object to be moved using a vibration actuator as a driving source, comprising: a substantially rod-shape vibration member, said vibration member including a first recess formed about the entire circumference of the vibration member and extending radially inward from the outer circumference of the vibration member, and a second recess contiguous with said first recess and extending in an axial direction of the vibration member, the second recess being located at a position radially interior to the first recess;   an electro-mechanical energy conversion element portion for generating a vibration in said vibration member; and   a contact member contactable to said vibration member and arranged for receiving the vibration therefrom to cause relative movement between said vibration member and said contact member.   
     
     
       24. An apparatus according to claim 23, wherein said apparatus is a printing apparatus, and said contact member is a movable member for feeding a sheet in the printing apparatus. 
     
     
       25. An apparatus according to claim 23, wherein said apparatus is a printing apparatus, and said contact member is a movable member for moving a carriage in the printing apparatus.